Add DEBUGPY_TRACE_DEBUGPY variable to allow debugpy to debug itself

Author: rchiodo

src/debugpy/common/log.py

@@ -58,7 +58,7 @@ def __init__(self, filename, file, levels=LEVELS, close_file=True):
                 platform.machine(),
                 platform.python_implementation(),
                 platform.python_version(),
-                64 if sys.maxsize > 2**32 else 32,
+                64 if sys.maxsize > 2 ** 32 else 32,
                 debugpy.__version__,
                 _to_files=[self],
             )

src/debugpy/common/messaging.py

@@ -21,6 +21,7 @@
 import threading
 
 from debugpy.common import json, log, util
+from debugpy.common.util import skip_trace
 
 
 class JsonIOError(IOError):
@@ -1148,9 +1149,11 @@ def start(self):
         self._parser_thread = threading.Thread(
             target=self._parse_incoming_messages, name=f"{self} message parser"
         )
-        self._parser_thread.pydev_do_not_trace = True
-        self._parser_thread.is_pydev_daemon_thread = True
-        self._parser_thread.daemon = True
+
+        if skip_trace():
+            self._parser_thread.pydev_do_not_trace = True
+            self._parser_thread.is_pydev_daemon_thread = True
+            self._parser_thread.daemon = True
         self._parser_thread.start()
 
     def wait(self):

src/debugpy/common/sockets.py

@@ -7,6 +7,7 @@
 import threading
 
 from debugpy.common import log
+from debugpy.common.util import skip_trace
 
 
 def create_server(host, port=0, backlog=socket.SOMAXCONN, timeout=None):
@@ -114,9 +115,10 @@ def accept_worker():
             handler(sock)
 
     thread = threading.Thread(target=accept_worker)
-    thread.daemon = True
-    thread.pydev_do_not_trace = True
-    thread.is_pydev_daemon_thread = True
+    if skip_trace():
+        thread.daemon = True
+        thread.pydev_do_not_trace = True
+        thread.is_pydev_daemon_thread = True
     thread.start()
 
     return listener

src/debugpy/common/util.py

@@ -148,3 +148,18 @@ def srcnameof(obj):
         name += ")"
 
     return name
+
+
+def skip_trace():
+    """Returns True if tracing should be skipped for the current thread."""
+    return "DEBUGPY_TRACE_DEBUGPY" not in os.environ
+
+
+def disable_tracing(thread):
+    """Disables tracing for the given thread if DEBUGPY_TRACE_DEBUGPY is not set.
+    DEBUGPY_TRACE_DEBUGPY is used to debug debugpy with debugpy
+    """
+    if skip_trace():
+        thread.pydev_do_not_trace = True
+        thread.is_pydev_daemon_thread = True
+        thread.daemon = True

src/debugpy/launcher/handlers.py

@@ -10,6 +10,7 @@
 from debugpy.common import json
 from debugpy.launcher import debuggee
 
+
 def launch_request(request):
     debug_options = set(request("debugOptions", json.array(str)))
 

src/debugpy/server/api.py

@@ -14,7 +14,7 @@
 from debugpy.common import json, log, sockets
 from _pydevd_bundle.pydevd_constants import get_global_debugger
 from pydevd_file_utils import absolute_path
-
+from debugpy.common.util import skip_trace
 
 _tls = threading.local()
 
@@ -129,9 +129,10 @@ def debug(address, **kwargs):
             "patch_multiprocessing": _config.get("subProcess", True),
         }
 
-        debugpy_path = os.path.dirname(absolute_path(debugpy.__file__))
-        settrace_kwargs["dont_trace_start_patterns"] = (debugpy_path,)
-        settrace_kwargs["dont_trace_end_patterns"] = (str("debugpy_launcher.py"),)
+        if skip_trace():
+            debugpy_path = os.path.dirname(absolute_path(debugpy.__file__))
+            settrace_kwargs["dont_trace_start_patterns"] = (debugpy_path,)
+            settrace_kwargs["dont_trace_end_patterns"] = (str("debugpy_launcher.py"),)
 
         try:
             return func(address, settrace_kwargs, **kwargs)

src/debugpy/server/cli.py

@@ -109,7 +109,7 @@ def do(arg, it):
             port = int(port)
         except Exception:
             port = -1
-        if not (0 <= port < 2**16):
+        if not (0 <= port < 2 ** 16):
             raise ValueError("invalid port number")
 
         options.mode = mode